Big Problem
 

So it all started yesterday when I left my car to get my audio install done at a shop. After running the cables and positioning all the equipment, the car would start. First thing that came to mind was that the steering wheel lock failed so I had it towed to the dealer. First thing this morning, I go to the dealer and they replace the steering wheel lock mechanism and the car still wont start. After tracing all the cables from the audio install, the main power cable was run through the firewall and apparently got cut while being pushed through the sharp hole. Long story short, metal contact on the exposed wiring and my entire car shorted out. Has this happened to anyone??? I am hoping the shop will pay for the repairs if in deed the issue was the install. I was told by the mechanic that at the very least my BCM is fried and needs to be replaced...... :eek2:

Crappy shops do crappy work and especially if they did not fuse the wire they used.

I take it they ran a new power wire for amps?

To be honest they are not a crappy shop I have dealt with them before and yes they ran the power wire through the firewall.... I supplied the cables and purchased an Audison amp kit so that wasnt an issue. Pretty much the wire got snagged and cut through the sheilding

Well it sounds like they either did not bother to install a fuse at maximum of 12 inches from the battery terminal.

Or the fuse was to big to blow to save your electronics. Either way I am looking at the shop.

IIRC, the fuse block was installed but I want to say it was only 32 Amps and the mechanic at the dealer stated that it was not enough to save the car.....

Sounds expensive

You have me scared....
 

Okay, this must be one more reason to not use the firewall plug below the brake booster.....Also, what should anyone be using for an inline fuse? Size???
I hear 50, see 150???? Am in the midst of this exact same install, other than I chose to run the cable through the same access point the factory uses. Man, that urethane adhesive they use to seal that connection is a bear to work through...
Anyway, guess this is why you carry insurance or at least have the work done by someone with a bond.....
Don't stop until it's fixed correctly.... And take plenty of notes along with good pictures...Best of luck to you.
Pat

The one directly behind the battery would be the best one to use.


OP a 32 Amp fuse? you sure? And the guy that told you it was not big enough to save your car should of said it was not SMALL enough to save your car. As you needed a smaller amp load to trip however it should of blown instantly if the 12 volt wire got grounded out.

holy crap. why would a shop not insulate the hole in the firewall when running live wire? wtf... failed install

So far this whole story isnt making a bit of sense. Any shop that has been in business for at least the last 5 years should know of the factory grommet behind the battery of every nissan and infiniti vehicle made since 04. Second ive never heard of a 32amp fuse that came with anyone's amp kit especially audison. Third if the wire did snag on metal and the no fuse in the car popped there should have been some fire or burned wires or something. It sounds like it could have been a bad install or your mechanic is BSing you

I need pics!!!!!! Under the hood, where the wire was ran and what it was ran through, where and how it gets to the rear.

Power line fuse is designed to protect the battery and car fire.

The fuse per IASCA rule must be installed no more than 12" from the battery terminals since it is unlikely anything might cause a short within that range. In the event of an accident, overload, short to ground (as in your case), the fuse should blow. The amperage has to do with the design for the TOTALITY of the load. The load (amperage) effect the wire gauge (size) and at a given length. Proper fuse sizes are dependent on the amount of amperage drawn by the amplifier(s). Wire size are not only dependent on the amperage drawn but also the length run. Typical for the main power cable is about 20' in an average car. So for a 50 to 70 amp fuse, you would need to have a 4 gauge wire. Higher gauge (2, 1, 0. etc) can be use but not necessary given the length run and amperage drawn.

To break it down in simple terms, a fuse is merely a conduit that is designed to break should the load is above rated draw that can be handled by the wire. It is there to protect the cable from overheating and melting the sheath thus causing a fire. So the fuse amperage should never be more than the design of the wire's capability. So running a 70 amp fuse on a 16 gauge wire will turn your 16 gauge wire into a heating coil in the event of a short because the 16 gauge wire will melt before the fuse does.

The fact that your car did not start might be trace to the poor install but I would consider resetting everything before deeming the "BCM fried". Disconnect the power cable to the amps at the battery. Double check the battery for damage, in-fact use a new battery if possible. Re-sett the car and go from there. I doubt it caused that much problem since the short if causes by the power cables grounding to chasis would be a closed system and should not have effected the car's BCM.

:iagree:

firewall punch threw
 

Can anyone show me a picture of the best place to punch threw the firewall on a 2012 370z so I can run some wire though to a switch in the cabin? Is there one behind the battery at all? :shakes head:

I'm trying to install a set of DDL's and need to find a safe place to punch the lines through to a switch in the cabin I'm going to install. Wanted to see if you could provide a picture of where you are talking about cause I can't find it....2012 370z. Thanks in advance.